1. Field of the Invention
The present invention generally relates to single-dose disposable containers for delivering reagents, medical solutions and the like. More particularly, this invention relates to an improved reagent containment and delivery tray for efficient gravity flow delivery of liquid reagent contained therein.
2. Description of the Prior Art
In a variety of medical and laboratory applications, it is necessary for various liquid medicaments and other fluids and reagents to be packaged in small glass or plastic "unit-dose" containers or vials which hold a small quantity of fluid, usually the amount normally required for a single dose to be used for patient administration or other application-specific purposes.
In laboratory applications, in particular, diagnostic tests typically require the input of precise amounts of liquid reagent at one or more points in the assay procedure used with the tests. In such cases, it is critical that the unit-dose container provide efficient delivery of a precise volume of liquid analytical reagent with a finely controlled coefficient of variation. Reagent delivery arrangements for such diagnostic test systems are generally expected to satisfy the following basic requirements: (i) low cost; (ii) extended shelf life (typically, at least about 18 months); (iii) delivery coefficients of variation ("CV") of about 1% independent of operator actuation; and (iv) a reagent containment capacity of up to 1 milliliter (mL).
Presently, the most commonly employed means of supplying and delivering precise amounts of reagent or fluid in a disposable container consists of a sealed container such as a glass syringe barrel prepacked with the liquid reagent contained between a movable piston and a septum which is pierced by the exertion of mechanical force using a needle-like member provided within or outside the system. The arrangement is such that the application of mechanical force to the movable piston following piercing of the septum drives out the liquid reagent contained within the syringe barrel. Such delivery systems are fairly expensive and mechanically complex and are generally incapable of high precision delivery of accurate amounts of liquid reagent contained within the syringe.
Another commonly employed delivery system is the use of sealed glass ampules or vials which are either (i) penetratable by syringes or like devices at the point of application for extracting the requisite dosage of reagent stored therein or (ii) adapted to be broken or otherwise opened up at the point of use. Such systems suffer from a marked lack of precision in delivery since expulsion of the total volume of the contained fluid cannot be ensured and also due to the uncontrollable nature of the glass particles produced when the vials are broken. Further, glass vials are relatively expensive and require careful handling to prevent accidental breakage and rigid quality control procedures to detect minute cracks in the vials or glass particles in the fluid contained within the vials.
Although many of these shortcomings are avoided by the use of plastic vials, penetratable containers or vials made of both plastic and glass are susceptible to cutting or coring of the material used to form the penetratable portions during insertion of the needle or like member. Accordingly, these arrangements are susceptible to serious contamination problems because of the possibility that particles of the container material may either fall into the vial or become lodged in the lumen of the extracting device.
As a result, there exists a distinct need for a low-cost, high-precision liquid containment and delivery system which is particularly adapted to the accurate and convenient delivery of extremely small unit doses of the order of about 1 mL.